The White House refrained from offering an on the record comment Tuesday about a U.S. airstrike Friday in Afghanistan that accidentally killed six innocent civilians, including five children.

Obama administration officials said the Pentagon and the International Security Assistance Force normally handle such incidents, though the administration "obviously has sought to reduce civilian casualties."

Pentagon spokesman Captain John Kirby said NATO does everything it can to prevent civilian casualties.

"We work very, very hard not to cause collateral damage or civilian casualties, exceptionally hard," Kirby said. "And when it happens as tragic as it is, it's by mistake, it's an accident."

When they occur, he said, "we own up to it, we take responsibility, we investigate it." He countered the coalition's position with the Taliban whom he said "do it wantonly, recklessly, sometimes with the intent to cause harm to civilians, and they don't take it anywhere near as seriously. "

Kirby said ISAF commander Gen. John Allen had met with Afghan President Hamid Karzai and had taken responsibility "for the casualties that we caused." He said "we take each one very, very seriously. They're all a tragedy."

In March, 120 members of ISAF, the Afghan government, and other groups convened the third Civilian Casualty Conference to talk about ways to reduce civilian deaths.

Allen declared that "preventing civilian casualties is a top priority…We have worked hard to take extensive measures to prevent civilian casualties, and those efforts are getting results."

Civilian casualties came at a time when Allied planes flying over Afghanistan have dropped fewer bombs in Afghanistan. According to statistics compiled by the Air Force, through the end of April, coalition aircraft released weapons 654 times this year, just under half the 1,247 weapons releases during that same time period in 2011.

At the Civilian Casualty Conference, Lt. Gen. Adrian Bradshaw, ISAF deputy commander, noted that in the previous four months, "insurgents have caused 93 percent, or 958 civilian casualties" mostly with improvised explosive devices. "In the same period of time, seven percent, or 72 civilian casualties, regrettably, were caused by ISAF forces," he added. "It is important to note though that compared to the same period of time last year, ISAF caused civilian casualties have been reduced by 65 percent."

Allen said that one Afghan civilian casualty caused by ISAF forces is too many.